Copper(I)-Catalyzed Regio- and Stereoselective Intramolecular Alkylboration of Propargyl Ethers and Amines
作者:Hiroaki Iwamoto、Yu Ozawa、Koji Kubota、Hajime Ito
DOI:10.1021/acs.joc.7b02071
日期:2017.10.6
transformed into multisubstituted alkenes through stereospecific transformations. Mechanistic studies showed that the chemo- and stereoselectivity of copper(I)-catalyzed borylation depends on the type of leaving group. Density functional theory calculations suggested that the regioselectivity of the borylcupration of the alkyne is controlled by the electronic effect of the oxygen atom of the propargyl ether
Copper(I)-Catalyzed Substitution of Propargylic Carbonates with Diboron: Selective Synthesis of Multisubstituted Allenylboronates
作者:Hajime Ito、Yusuke Sasaki、Masaya Sawamura
DOI:10.1021/ja806602h
日期:2008.11.26
A versatile synthetic method for the preparation of the allenylboronates, Cu(I)-catalyzed reaction of propargylic carbonates with a diboron, is described. A Cu(O-t-Bu)-Xantphos catalyst system was effective for the preparation of various allenylboron compounds, allenylboronates with different substitution patterns, those with functional groups, and an axially chiral one. The Lewis acid promoted stereoselective addition to aldehydes leading to homopropargylic alcohols showed the usefulness of the new allenylboronates.